Vibrationally isolated cryogenic shield for local high-quality vacuum

ABSTRACT

The disclosure describes various aspects of a vibrationally isolated cryogenic shield for local high-quality vacuum. More specifically, the disclosure describes a cryogenic vacuum system replicated in a small volume in a mostly room temperature ultra-high vacuum (UHV) system by capping the volume with a suspended cryogenic cold finger coated with a high surface area sorption material to produce a localized extreme high vacuum (XHV) or near-XHV region. The system is designed to ensure that all paths from outgassing materials to the control volume, including multiple bounce paths off other warm surfaces, require at least one bounce off of the high surface area sorption material on the cold finger. The outgassing materials can therefore be pumped before reaching the control volume. To minimize vibrations, the cold finger is only loosely, mechanically connected to the rest of the chamber, and the isolated along with the cryogenic system via soft vacuum bellows.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to and the benefit of U.S.Provisional Patent Application No. 62/616,859, entitled “VIBRATIONALLYISOLATED CRYOGENIC SHIELD FOR LOCAL HIGH-QUALITY VACUUM,” and filed onJan. 12, 2018, the contents of which are incorporated herein byreference in their entirety.

BACKGROUND OF THE DISCLOSURE

Aspects of the present disclosure generally relate to different atomicsystems including quantum computing or quantum information processing(QIP) systems, and more specifically, to a vibrationally isolated coldfinger and/or cryogenic shield for local high-quality vacuum.

Individual optically-active quantum systems such as trapped atoms areone of the leading implementations for quantum information processing.Atom-based quantum bits (qubits) can be used as quantum memories, canhost quantum gates in quantum computers and simulators, and can act asnodes for quantum communication networks. Qubits based on trapped atomicions enjoy a rare combination of attributes. For example, qubits basedon trapped atomic ions have very good coherence properties, can beprepared and measured with nearly 100% efficiency, and are readilyentangled with each other by modulating their Coulomb interaction orthrough remote photonic interconnects. Lattices of cold (e.g.,laser-cooled) trapped atoms have also proven useful for precisionmetrology, including sensors of small forces and atomic clocks.

Atomic ions are typically loaded into traps by creating a neutral atomicflux of the desired particle and ionizing them once in the trappingvolume. Ions can remain confined for months, with lifetimes oftenlimited by the level of vacuum. Reloading of the ions into the trapafter loss of one or more ions may reduce the fraction of the time thatthe ions are used for applications such as QIP. Thus it is desirable toincrease the ion lifetimes by providing the highest quality vacuumcompatible with the application.

For QIP systems that rely on trapped ion technology, generating regionsof extreme high vacuum (XHV) or even vacuum approaching XHV (i.e.,near-XHV) may be a challenge because of the outgassing of chambermaterials. Even stainless steel, one of the most widely used materialsin ultra-high vacuum (UHV) applications, introduces large quantities ofhydrogen gas into the vacuum. Cooling chambers to cryogenic temperatures(e.g., 4K) may greatly reduce the outgassing pressures of the materialsand may provide pumping of materials that freeze on the surfaces or aretrapped by cryogenic sorption. Cryogenic operations, however, placelimits on the connectivity of devices and components in a vacuum system,may also limit the power loads of those devices and components, and mayintroduce vibration from either the piston motion of the closed cyclecryostats or the flow/boiling of cryogens in the flow cryostats.

Accordingly, techniques that can provide regions of XHV or near-XHVwhile retaining the benefits of room temperature UHV may be desirable inatomic systems (e.g., QIP systems, clocks, and sensor) that rely ontrapped ion technology.

SUMMARY OF THE DISCLOSURE

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its purpose is to presentsome concepts of one or more aspects in a simplified form as a preludeto the more detailed description that is presented later.

In an aspect of the disclosure, various techniques are described inwhich many of the benefits of a cryogenic vacuum system may bereplicated in a small, controlled volume (e.g., pillbox) in a mostlyroom temperature UHV system by capping the volume with a suspendedcryogenic cold finger that may be partially or fully coated in a highsurface area cryogenic sorption material. The cold finger may act as acryogenic pump. One of the features of such implementation is that thesystem is configured to ensure that all paths from outgassing materialsto the controlled or critical volume (including multiple bounce pathsoff of other warm surfaces) require at least one bounce off of the highsurface area materials on the cold finger. In that case, the outgassingmaterial may be pumped before it can reach the controlled volume. Tominimize vibrations from the cryogenic system cooling the cold finger,the cold finger may be only loosely mechanically connected to the restof the chamber. In one aspect, the cold finger may be isolated alongwith the cryogenic system via a soft vacuum bellows. In oneimplementation, an XHV or near-XHV volume may be configured above oraround an ion trap using a suspended cold finger.

In an aspect of the disclosure, a cryogenic device for use in a vacuumchamber is described that includes a suspended cold finger that forms acapping volume that covers or encloses a device under test (DUT),wherein the capping volume formed by the suspended cold finger isconfigured to have outgassing materials bounce off the cryogenicsorption material before reaching a critical volume over the DUT. Acryogenic sorption material having a large surface area can be depositedon one or more surfaces of the cold finger. In an example, the DUT is atrap such as an ion trap. Moreover, the critical volume over the DUTprovides a localized region of XHV or near-XHV over the DUT while otherregions in the vacuum chamber provide UHV.

In another aspect of the disclosure a method for using a cryogenicdevice in a vacuum chamber is described that includes cooling asuspended cold finger of the cryogenic device that forms a cappingvolume that encloses a DUT, wherein the capping volume formed by thesuspended cold finger is configured to have outgassing materials bounceoff the cold finger before reaching a critical or controlled volume overthe DUT. The method further includes performing one or more quantumoperations using the DUT. In an example, the DUT is a trap such as anion trap. Moreover, the critical volume over the DUT provides alocalized region of XHV or near-XHV over the DUT while other regions inthe vacuum chamber provide UHV. A cryogenic sorption material having alarge surface area can be deposited on one or more surfaces of the coldfinger.

Each of the aspects described above can also be implemented using meansfor performing the various functions described in connection with thoseaspects.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended drawings illustrate only some implementation and aretherefore not to be considered limiting of scope.

FIG. 1A illustrates a view of a vacuum chamber that houses electrodesfor the trapping of atomic ions in accordance with aspects of thedisclosure.

FIG. 1B is a diagram illustrating an example of a simplified energylevel diagram showing the application of laser radiation for stateinitialization in accordance with aspects of the disclosure.

FIG. 1C is a diagram illustrating an example of a simplified energylevel diagram showing the application of laser radiation for qubit statedetection through fluorescence in accordance with aspects of thedisclosure.

FIG. 2 is a block diagram that illustrates an example of a quantuminformation processing (QIP) system in accordance with aspects of thisdisclosure.

FIG. 3A is a diagram that illustrates a cross sectional view of a vacuumchamber with a local high quality vacuum in accordance with aspects ofthis disclosure.

FIGS. 3B and 3C are diagrams that illustrate a cold finger for capping acontrolled or critical volume for XHV or near-XHV in a vacuum chamber inaccordance with aspects of this disclosure.

FIG. 4 is a flow diagram that illustrates an example of a method inaccordance with aspects of this disclosure.

FIG. 5 is a diagram that illustrates an example of a computer device inaccordance with aspects of this disclosure.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appendeddrawings is intended as a description of various configurations and isnot intended to represent the only configurations in which the conceptsdescribed herein may be practiced. The detailed description includesspecific details for the purpose of providing a thorough understandingof various concepts. However, it will be apparent to those skilled inthe art that these concepts may be practiced without these specificdetails. In some instances, well known components are shown in blockdiagram form in order to avoid obscuring such concepts. As used herein,the term “about” may refer to a value that is within 1%, 2%, 3%, 4%, 5%,10%. 15%, 20%, or 25% of a nominal value. In some instances, the term“about” may involve multiples of 2, 2.5, 3, 3.5, or 4 of a nominalvalue. For example, for cryogenic temperatures of about 4 degrees Kelvin(4K), the actual or practical temperatures may range to as much 10K,which is 2.5 times the nominal value of 4K.

As described above, trapped atoms may be used to implement quantuminformation processing. Atomic-based qubits can be used as differenttype of devices, including but not limited to quantum memories, thequantum bits in quantum computers and simulators, and nodes for quantumcommunication networks. Qubits based on trapped atomic ions (e.g., atomswith a net state of electrical charge) can have very good coherenceproperties, can be prepared and measured with nearly 100% efficiency,and can be readily entangled with each other by modulating their Coulombinteraction or through remote photonic interconnects. Lattices of cold(e.g., laser-cooled) trapped atoms have also proven useful for precisionmetrology, including sensors of small forces and atomic clocks. As usedin this disclosure, the terms “atoms,” “atomic ions,” and “ions” may beused interchangeably to describe the particles that are isolated andcontrolled, or are actually confined individually or as multiples withthe latter forming a diffuse cloud or a crystal lattice or similararrangement or configuration. Where the charge state of the atom(neutral atom or any charge state of the atomic ion) is not relevant,the disclosure describes techniques that can be used for any type ofneutral atom or atomic ion or other type of optically active quantumsystem. This disclosure describes techniques for a vibrationallyisolated cold finger and/or cryogenic shield for local high-qualityvacuum.

In the case of atomic ions, the typical ion trap geometry or structureused for quantum information and metrology purposes is the linearradio-frequency (RF) Paul trap (also referred to as an RF trap or simplya Paul trap), where nearby electrodes hold static and dynamic electricalpotentials that lead to an effective inhomogeneous harmonic confinementof the ions. The RF Paul trap is a type of trap that uses electricfields to trap or confine one or more charged particles in a particularregion, position, or location. When multiple atomic ions are loaded intosuch a trap are laser-cooled to very low temperatures, the atomic ionsform a stationary lattice of qubits (e.g., a structured arrangement ofqubits), with Coulomb repulsion balancing the external confinementforce. For sufficient trap anisotropy, the ions can form a linearlattice along the weak direction of confinement, and this is thearrangement typically employed for applications in quantum informationand metrology. As the trap anisotropy is reduced, the atomic ionsundergo a series of phase transitions in their static conformation inspace, evolving to a two-dimensional (2D) zig-zag or jagged typestructure, then a three-dimensional (3D) helical structure, ultimatelytoward a spherical lattice when the three directions of confinementapproach isotropy.

FIG. 1A illustrates a partial view of a vacuum chamber 100 that houseselectrodes for the trapping of atomic ions in a linear lattice orcrystal 110 using a linear RF Paul trap. Although not shown, it is alsopossible to trap single atomic ions using an RF Paul trap. In theexample shown in FIG. 1A, a vacuum chamber in a quantum system includeselectrodes for trapping one or more atomic Ytterbium ions (e.g., ¹⁷¹Yb⁺ions) which are confined in the linear lattice 110 and are laser-cooledto be nearly at rest. While multiple atomic ions are shown in thisexample, the number of atomic ions trapped can be configurable and moreor fewer than the number of atomic ions shown may be trapped including,but not limited to, the configuration with a single ion being trapped.The atoms are illuminated with laser radiation tuned to a resonance in¹⁷¹Yb⁺ and the fluorescence of the atomic ions is imaged onto a camera.In this example, atomic ions are separated by a distance 115 of about 5microns (μm) from each other as shown by fluorescence. The separation ofthe atomic ions is determined by a balance between the externalconfinement force and Coulomb repulsion.

Atomic ions are typically loaded into traps by creating a neutral atomicflux of the desired particle, and ionizing them once in the trappingvolume. Ions can remain confined for months, with lifetimes oftenlimited by the level of vacuum. Elastic collisions with residualbackground gas occur roughly once per hour per ion at typical ultra-highvacuum (UHV) pressures (˜10⁻¹¹ torr) and these collisions might or mightnot eject on ore more ions from the trap. Cryogenic chambers canvirtually eliminate these collision events by further reducing thebackground pressure by limiting the outgassing of materials andproviding pumping of gasses through mechanisms such as freezing ofgasses on cold surfaces and cryogenic sorption of gasses into highsurface area materials.

FIG. 1B and FIG. 1C show the reduced energy level diagrams 120 and 150,respectively, for an example species of atomic ion ¹⁷¹Yb⁺ where the twostates of the quantum bits (qubits) |↑

and |↓

130 are represented by the stable hyperfine levels in the groundelectronic state, and are separated approximately by frequencyω₀/2π=12.642 GHz. The excited electronic states |e

and |e′

140 in ¹⁷¹Yb⁺ are themselves split by a smaller hyperfine coupling andare separated from the ground states by an optical interval having anenergy corresponding to an optical wavelength of 369.53 nm.

In FIGS. 1B and 1C, all allowed transitions from the excited electronicstates |e

and |e′

140 are illustrated as downward, wavy arrows. On the other hand, theapplied laser radiation (which is shown as upward, straight arrows)drive these transitions for initialization to state |↓

as shown in FIG. 1B, and for fluorescence detection of the qubit state(|↑

=fluorescence, |↓

=no fluorescence) as shown in FIG. 1C.

Laser radiation tuned just below resonance in these optical transitionsallows for Doppler laser cooling to confine the atomic ions near thebottom of the trapping potential. Other more sophisticated forms oflaser cooling can bring the atomic ions to be nearly at rest in thetrap.

Below are described various techniques for creating a controlled volumeof XHV or near-XHV in a mostly room temperature UHV system. Thiscontrolled volume may be created by capping or surrounding the volumewith a suspended cryogenic cold finger that may be partially or fullycoated in a high surface area cryogenic sorption material. The coldfinger may act as a cryogenic pump and the system is configured toensure that all paths from outgassing materials to the controlled orcritical volume (including paths from warm surfaces) require at leastone bounce off of the cold finger such that the outgassing material maybe pumped before it can reach the controlled volume. To minimizevibrations from the cryogenic system cooling the cold finger, the coldfinger may be only loosely mechanically connected to the rest of thechamber. The cold finger may be isolated along with the cryogenic systemvia a soft vacuum bellows.

As used herein, the term UHV may refer to a pressure range between about10⁻⁷ and about 10⁻¹⁰ Pa, while the term XHV may refer to a range ofpressure below about 10⁻¹⁰ Pa (7.5×10⁻¹³ Torr or 10⁻¹² mbar). Here, werefer to near-XHV as UHV vacuum that is approaching the XHV range.

FIG. 2 shows a block diagram 200 that illustrates an example of a QIPsystem 205 in accordance with aspects of this disclosure. The QIP system205 may also be referred to as a quantum computing system, a computerdevice, or the like. In an aspect, the QIP system 205 may correspond toportions of a quantum computer implementation of the computing device500 in FIG. 5.

The QIP system 205 can include a source 260 that provides atomic species(e.g., a flux of neutral atoms) to a chamber 250 (see e.g., the vacuumchamber 100 in FIG. 1A) having an ion trap 270 that traps the atomicspecies once ionized (e.g., photoionized) by an optical controller 220.The source 260 may be part of the chamber 250 (or may be implementedseparate from and outside of the chamber 250) and can include a thermalatom source or atomic oven source to produce a flux. Optical sources 230in the optical controller 220 may include one or more laser sources thatcan be used for ionization of the atomic species, control (e.g., quantumstate control) of the atomic ions, for fluorescence of the atomic ionsthat can be monitored and tracked by image processing algorithmsoperating in an imaging system 240 in the optical controller 220, andfor overall control of optical operations associated with the atomicions in the ion trap 270. The imaging system 240 can include a highresolution imager (e.g., CCD camera) for monitoring the atomic ionswhile they are being provided to the ion trap 270 (e.g., for counting)or after they have been provided to the ion trap 270 (e.g., formonitoring the atomic ions states). In an aspect, the imaging system 240can be implemented separate from the optical controller 220, however,the use of fluorescence to detect, identify, and label atomic ions usingimage processing algorithms may need to be coordinated with the opticalcontroller 220.

Although not shown, one or more radio-frequency (RF) amplifiers may beused to provide RF potential to the ion trap 270 for operation, as wellas one or more DC sources also to be used with the ion trap 270.Moreover, the chamber 250 may include a cold finger 275 and a cryogenicshield 277, where one or both of these may be used to produce acontrolled or critical volume over the ion trap 270 to provide ahigh-quality vacuum (e.g., XHV). An example of a chamber with a coldfinger and a cryogenic shield is described in more detail below withrespect to FIGS. 3A-3C.

The QIP system 205 may also include an algorithms component 210 that mayoperate with other parts of the QIP system 205 (not shown) to performquantum algorithms or quantum operations. As such, the algorithmscomponent 210 may provide instructions to various components of the QIPsystem 205 (e.g., to the optical controller 220) to enable theimplementation of the quantum algorithms or quantum operations.

FIG. 3A shows a diagram 300 that illustrates a partial cross sectionalview of a vacuum chamber 310 with a localized high quality vacuum (e.g.,XHV) 330 in accordance with aspects of this disclosure. The vacuumchamber 310 may be an example of the chamber 250 in FIG. 2 or the vacuumchamber 100 in FIG. 1A. The vacuum chamber 310 may include a mountingsystem 320 on which to place a device under test (DUT) 325. The DUT 325may correspond to a trap such as an ion trap (e.g., the ion trap 270 inFIG. 2) or may correspond to a different device being tested or used forquantum computations. The vacuum chamber 310 or components within thevacuum chamber (e.g., the mounting system 320) may be cooled or heatedas required by the application or component use. For example, inaddition to cooling a trap it is also possible to heat sensors such as avacuum gauge. Parts of the vacuum chamber 310 may have unwantedoutgassing properties. For example, the mounting system 320 may haveunwanted outgassing properties, however, these may be limited bycontrolling the line of sight (e.g., path) from the mounting system 320to a critical volume 330. For example, the mounting system 320 (as wellas other components of the vacuum chamber 310) may be made of stainlesssteel and may introduce hydrogen gas into the vacuum. The criticalvolume 330 may refer to a volume, space, or region just above the DUT325 within which high quality vacuum (e.g., XHV) is achieved. It is tobe understood that other volumes, spaces, or regions within the vacuumchamber 310 may achieve UHV and that the improved vacuum (e.g., XHV) islocalized to the critical volume 330.

The critical volume 330 may be enveloped or capped by a volume, space,or region produced by the configuration or shape of a cold finger 340.The cold finger 340 may be cooled to about 4 degrees Kelvin (4K) and mayhave one or more surfaces that surround the critical volume 330 and arecovered with a high surface area cryogenic sorption material 345, whichmay also operate at about 4K. The cold finger 340 may include a windowor hole 347 through which laser beams may be directed at the DUT 325.

FIG. 3B shows a diagram 303 that illustrates how the configuration andplacement of the cold finger 340 restricts outgassing (represented bydashed lines with arrows 327) from, for example, the mounting system 320to contact the high surface area cryogenic sorption material 345 beforereaching the critical volume 330. At the contact with the sorptionmaterial 345, there is a likelihood that the outgassing material will becaptured (absorped) by the sorption material 345 and prevented fromcontinuing to the critical volume 330.

FIG. 3C shows a diagram 305 that illustrates an example of how the coldfinger 340 may include various inner surfaces covered by the highsurface area cryogenic sorption material 345 surrounding the DUT 325and/or the critical volume 330 to achieve the XHV or near-XHV within thecritical volume 330.

Returning to FIG. 3A, the vacuum chamber 310 may include a vacuumviewport 315 of a very low outgassing material. This surface may have aregion with a line of sight to the critical volume 330. Line-of-site tothis region of the vacuum viewport 315 by outgassing materials may becontrolled by the placement and configuration of the cold finger in sucha way as to require outgassing (represented by dashed lines with arrows313 in FIG. 3B) from surrounding materials to bounce at least once fromthe cold finger 340 (which may be coated with sorption material) beforethey can reach this line-of-site region on the vacuum viewport 315. Whenthe outgassing bounces on the cold finger 340, there is a change of theoutgassing being captured onto the cold finger (i.e. freezing out ontothe surface or being absorbed by a coating of sorption material). Thisaspect may allow for there to be openings and/or windows in the coldfinger 340.

Also shown in FIG. 3A and FIG. 3B is a cryogenic shield 350 that ispositioned near the cold finger 340 and is configured to reduce athermal loading of the cold finger 340. In the example shown in FIG. 3A,there are two cryogenic shields 350 shown which may be connected aroundthe sides of the cold finger 340 (not shown in the partial crosssectional view of FIG. 3A). The cryogenic shield 350 may include (shownwith a dotted line) an opening or window 355. A window might be usedthere to isolate the critical volume 330 from a warm surface of thevacuum viewport 315 via a cold window surface and/or to reduce thermalload on the cold finger 340 by absorbing or reflecting infra-red (IR)light coming from outside the vacuum chamber 310. However, the additionof such a window 355 might couple some motion of the phase/angle of thelaser going through it so the use or implementation of the window 355may depend on the particular needs of the experiment or operationassociated with the vacuum chamber 310.

Attached or coupled to the vacuum chamber 310 are a room temperature ionpump 380, a cryogenic cooler 370 that cools the cold finger 340, and thecryogenic shield 350. The cryogenic cooler 370 may be coupled to thevacuum chamber 310 via soft vacuum bellows 375 to reduce transfer ofvibrations from the cryogenic cooler to the vacuum chamber.

Also shown in FIG. 3A is a cryogenic head 360 that extends from, and ispart of, the cryogenic cooler 370. The cryogenic head 360 is configuredto connect to the cold finger 340 to cool the cold finger 340 to atemperature of about 4K (in practice this temperature can range up toabout 10 K). The cryogenic head 360 is also configured to connect to thecryogenic shield 350 to cool the cryogenic shield 350 to a temperatureof about 40K (in practice this temperature can range up to about 3 timesthe 40K). Although not shown, the connection of the cryogenic head 360to the cryogenic shield(s) 350 may occur closer to the cryogenic cooler370 than the connection of the cryogenic head 360 to the cold finger340.

Therefore, by adding a cold finger (e.g., the cold finger 340) to createa controlled vacuum volume with high quality vacuum it may be possibleto get some of the benefits of cryogenic systems while also providingmechanical rigidity for the DUT 325 to the vacuum chamber 310.

In an aspect of this disclosure, the vacuum chamber 310 shown in FIG. 3Aand cryogenic cold finger 345 may be supplemented with cooling of theDUT 325 (e.g., ion trap) and possibly nearby components (e.g., themounting system 320) to reduce outgassing from the material of the DUT325 and surrounding components. Cooling for the purpose of reducingoutgassing from the DUT 325 and surrounding components may not requireas low a temperature as needed for the cold finger 340, and may beachieved using techniques such as liquid nitrogen cooling lines, that donot introduce vibrations and can handle higher thermal loads than thecryogenic cooler used for the cold finger.

It is to be understood that the various components and/or parts shown inFIGS. 3A-3C may not be drawn to scale and are provided by way ofillustration and not of limitation. The dimensions, spacing, andpositioning of the various components and/or parts shown in FIGS. 3A-3Cmay be exaggerated for clear illustration.

FIG. 4 is a flow diagram that illustrates an example of a method 400 forusing a vacuum chamber with a localized XHV or near-XHV in a QIP systemin accordance with aspects of this disclosure. In an aspect, the method400 may be performed in a computer system such as the computer system500 described below. Similarly, the functions of the method 400 may beperformed by one or more components of a QIP system such as the QIPsystem 205 and its components, where the QIP system can include an iontrap. For example, the method 400 may be performed in connection withthe chamber 250 in FIG. 2 or the vacuum chamber 310 in FIG. 3A and/orother components configured to operate, control, interact, and/orconfigure the chamber 250 or the vacuum chamber 310.

At 410, the method 400 includes cooling a suspended cold finger of thecryogenic device that forms a capping volume that encloses a DUT,wherein the capping volume formed by the suspended cold finger isconfigured to have outgassing materials bounce off of the cold fingerbefore reaching a critical volume. In an aspect, the DUT is a trap suchas an ion trap. Moreover, the cold finger may be cooled to about 4K. Acryogenic sorption material having a large surface area can be depositedon one or more surfaces of the cold finger.

At 420, the method 400 includes performing one or more quantumoperations using the DUT.

In an aspect of the method 400, the critical volume over the DUTprovides a localized region of XHV or near-XHV over the DUT while otherregions in the vacuum chamber provide UHV.

In another aspect of the method 400, the cryogenic device includes ashield configured to reduce thermal loading of the cold finger. Themethod may further include cooling the shield to about 40K.

In another aspect of the method 400, the method may further includeperforming room temperature vacuum pumping of the vacuum chamber usingan ion pump.

In yet another aspect of the method 400, the method may further includevibrationally isolating the cold finger from the vacuum chamber by softvacuum bellows.

Referring now to FIG. 5, illustrated is an example computer device 500in accordance with aspects of the disclosure. The computer device 500can represent a single computing device, multiple computing devices, ora distributed computing system, for example. The computer device 500 maybe configured as a quantum computer, a classical computer, or acombination of quantum and classical computing functions. For example,the computer device 500 may be used to process information using quantumalgorithms based on trapped ion technology and may therefore implement avacuum chamber with a localized XHV or near-XHV volume as describedabove. As described above, the QIP system 205 may be an example of atleast a portion of the computer device 500.

In one example, the computer device 500 may include a processor 510 forcarrying out processing functions associated with one or more of thefeatures described herein. The processor 510 may include a single ormultiple set of processors or multi-core processors. Moreover, theprocessor 510 may be implemented as an integrated processing systemand/or a distributed processing system. The processor 510 may include acentral processing unit (CPU), a quantum processing unit (QPU), agraphics processing unit (GPU), or combination of those types ofprocessors. In one aspect, the processor 510 may refer to a generalprocessor of the computer device 510, which may also include additionalprocessors 510 to perform more specific functions such as control of theoperations (e.g., cooling, pumping) of a vacuum chamber, for example.

In an example, the computer device 500 may include a memory 520 forstoring instructions executable by the processor 510 for carrying outthe functions described herein. In an implementation, for example, thememory 520 may correspond to a computer-readable storage medium thatstores code or instructions to perform one or more of the functions oroperations described herein. In one example, the memory 520 may includeinstructions to perform aspects of a method 400 described below inconnection with FIG. 4. Just like the processor 510, the memory 520 mayrefer to a general memory of the computer device 500, which may alsoinclude additional memories 520 to store instructions and/or data formore specific functions such as instructions and/or data for control ofthe operations (e.g., cooling, pumping) of a vacuum chamber, forexample.

Further, the computer device 500 may include a communications component530 that provides for establishing and maintaining communications withone or more parties utilizing hardware, software, and services asdescribed herein. The communications component 530 may carrycommunications between components on the computer device 500, as well asbetween the computer device 500 and external devices, such as deviceslocated across a communications network and/or devices serially orlocally connected to computer device 500. For example, thecommunications component 500 may include one or more buses, and mayfurther include transmit chain components and receive chain componentsassociated with a transmitter and receiver, respectively, operable forinterfacing with external devices.

Additionally, the computer device 500 may include a data store 540,which can be any suitable combination of hardware and/or software, thatprovides for mass storage of information, databases, and programsemployed in connection with implementations described herein. Forexample, the data store 540 may be a data repository for operatingsystem 560 (e.g., classical OS, or quantum OS). In one implementation,the data store 540 may include the memory 520.

The computer device 500 may also include a user interface component 550operable to receive inputs from a user of the computer device 500 andfurther operable to generate outputs for presentation to the user or toprovide to a different system (directly or indirectly). The userinterface component 550 may include one or more input devices, includingbut not limited to a keyboard, a number pad, a mouse, a touch-sensitivedisplay, a digitizer, a navigation key, a function key, a microphone, avoice recognition component, any other mechanism capable of receiving aninput from a user, or any combination thereof. Further, the userinterface component 550 may include one or more output devices,including but not limited to a display, a speaker, a haptic feedbackmechanism, a printer, any other mechanism capable of presenting anoutput to a user, or any combination thereof.

In an implementation, the user interface component 550 may transmitand/or receive messages corresponding to the operation of the operatingsystem 560. In addition, the processor 510 may execute the operatingsystem 560 and/or applications or programs, and the memory 520 or thedata store 540 may store them.

When the computer device 500 is implemented as part of a cloud-basedinfrastructure solution, the user interface component 550 may be used toallow a user of the cloud-based infrastructure solution to remotelyinteract with the computer device 500.

Although the present disclosure has been provided in accordance with theimplementations shown, one of ordinary skill in the art will readilyrecognize that there could be variations to the embodiments and thosevariations would be within the scope of the present disclosure.Accordingly, many modifications may be made by one of ordinary skill inthe art without departing from the scope of the appended claims.

What is claimed is:
 1. A cryogenic device for use in a vacuum chamber,comprising: a suspended cold finger that forms a capping volume thatcovers or encloses a device under test (DUT), wherein the capping volumeformed by the suspended cold finger is configured to have outgassingmaterials bounce off of the cold finger before reaching a criticalvolume over the DUT.
 2. The device of claim 1, wherein the DUT is atrap.
 3. The device of claim 1, wherein the trap is an ion trap.
 4. Thedevice of claim 1, wherein the critical volume over the DUT provides alocalized region of extreme high vacuum (XHV) or near-XHV over the DUTwhile other regions in the vacuum chamber provide ultra-high vacuum(UHV).
 5. The device of claim 1, wherein the cold finger is looselymechanically connected to the vacuum chamber.
 6. The device of claim 1,wherein the cold finger is isolated along with a cryogenic head via softvacuum bellows.
 7. The device of claim 1, further comprising a shieldconfigured to reduce thermal loading of the cold finger.
 8. The deviceof claim 7, wherein a cryogenic head is configured to cool both the coldfinger and the shield.
 9. The device of claim 8, wherein the cold fingeris cooled to about 4K and the shield is cooled to about 40K.
 10. Thedevice of claim 1, further comprising cryogenic sorption material thatis deposited on one or more surfaces of the cold finger.
 11. The deviceof claim 1, wherein the cold finger includes one or more openings toallow for optical access to the DUT.
 12. The device of claim 1, whereinthe cold finger is vibrationally isolated from the vacuum chamber bysoft vacuum bellows.
 13. The device of claim 1, wherein the DUT iscooled to about 70K by means of a low-vibration cooling operation.
 14. Amethod for using a cryogenic device in a vacuum chamber, comprising:cooling a suspended cold finger of the cryogenic device that forms acapping volume that encloses a device under test (DUT), wherein thecapping volume formed by the suspended cold finger is configured to haveoutgassing materials bounce off the cold finger before reaching acritical volume over the DUT; and performing one or more quantumoperations using the DUT.
 15. The method of claim 14, wherein the DUT isa trap.
 16. The method of claim 14, wherein the cold finger is cooled toabout 4K.
 17. The method of claim 14, wherein the critical volume overthe DUT provides a localized region of extreme high vacuum (XHV) ornear-XHV over the DUT while other regions in the vacuum chamber provideultra-high vacuum (UHV).
 18. The method of claim 14, wherein thecryogenic device includes a shield configured to reduce thermal loadingof the cold finger.
 19. The method of claim 18, further comprisingcooling the shield to about 40K.
 20. The method of claim 14, furthercomprising performing room temperature vacuum pumping of the vacuumchamber using an ion pump.
 21. The method of claim 14, furthercomprising vibrationally isolating the cold finger from the vacuumchamber by soft vacuum bellows.
 22. The method of claim 14, furthercomprising cooling the DUT to about 70K, wherein the cooling comprisesperforming a low-vibration cooling operation or method.
 23. The methodof claim 14, wherein a cryogenic sorption material having a largesurface area is deposited on one or more surfaces of the cold finger.